In 132 CE, Han Dynasty polymath Zhang Heng presented a bronze seismometer to the imperial court. 🐉 Eight dragon heads held copper balls above toads. The internal mechanism remains unknown, though later reconstructions propose a pendulum or balanced mass. The Book of the Later Han records a ball dropping to show an earthquake's direction. The famous episode concerns a 138 CE earthquake more than 500 li west of Luoyang—not 132—and whether the account reflects actual performance remains debated. 🌍
Zhang Heng's 132 AD seismoscope was credited with detecting a distant 138 AD quake
Key facts
- Zhang Heng, a Chinese polymath and Han court official, presented the seismoscope in 132 CE.
- Traditional descriptions show a bronze vessel with eight dragon heads, each holding a copper ball above a toad.
- The internal mechanism is unknown; a pendulum or balanced mass is a later reconstruction.
- The Book of the Later Han describes a dragon releasing its ball to indicate an earthquake's direction, not its precise location.
- The famous test is associated with a 138 CE earthquake more than 500 li west of Luoyang, not an earthquake in 132 CE.
- Whether the historical account reflects the instrument's actual performance remains debated.
Sources
The world's first seismometer used a toad to catch an earthquakenewscientist.com
Featuring bronze toads and dragons, a legendary tremor detector was made by polymath Zhang Heng in AD 132 – but did it really work? The evidence is shaky.
Zhang Heng - Wikipediaen.wikipedia.org
To indicate the direction of a distant earthquake, Zhang's device dropped a bronze ball from one of eight tubed projections shaped as dragon heads; the ball ...
Zhang Heng's dragon seismoscope · Creation.comcreation.com
This seismoscope, designed to detect when an earthquake had occurred and from what direction, was invented by Zhang Heng (AD 78–139). He was a ...
Ancient Seismometerchcp.org
an earthquake detector — was invented in 132 A.D., by Chang Heng, a brilliant mathematician and scientist in the Han Dynasty.
132 – Chinese Seismoscopedataphys.org
In AD 132, Zhang Heng of China's Han dynasty invented the first seismoscope … it was a large bronze vessel, about 2 meters in diameter; dragon's heads holding ...
Zhang Heng Seismoscope in Shanghaiatlasobscura.com
He invented his seismoscope in 132 CE. A seismoscope records disturbances along the earth's surface. The device Heng created was even able to ...
Was this story useful?
Keep exploring
Every site on this page sits on the globe, and the people who research them are on the Discord.
3D Globe · Sites by country · Story Archive · Research Library · Weekly Journal · Search
AI-generated text · images from the original sources · always verify with the sources.